(1) Field of the Invention
The present invention relates to a structure for mounting an electric motor in vehicles such as Electric Vehicles and Hybrid Vehicles.
(2) Description of Related Art
In recent years, techniques related to Electric Vehicles and Hybrid Vehicles have been developed to protect the global environment.
For example, the following related document 1 discloses a structure for mounting an electric motor in a vehicle.
The technique of the related document 1 will now be described briefly. In this part of the description, numerals in brackets correspond to numerals used in figures of the related document 1.
In the related document 1, as shown in FIG. 1 and FIG. 2, a parts-mounting frame (8) is disclosed which is comprised of two lateral frames (9) and a longitudinal frame (10) connecting the frames (9).
The related document 1 also discloses that a motor unit (15) is fixed on the bottom of the parts-mounting frame (8) by bolts (19 and 19). Further the document discloses that a control unit (11) is fixed on the upper side of the parts-mounting frame (8).
Furthermore, the document 1 discloses that the parts-mounting frame (8) is fixed to side members (5 and 5) via brackets (29 and 30).
Moreover, the document 1 discloses that, during assembly, a center member (23) is fixed to a first cross member (6) after the parts-mounting frame (8) is fixed to the side members (5). Further, it is also disclosed that the bolts (19) are removed after the side motor mount (22) is connected to a frame-side-mounting bracket (27)
[Related Document 1] H08 (1996)-310252 Japanese Laid-open Publication
However, by the technique of the related document 1, it is difficult to fully utilize the space above the parts-mounting frame (8) because the parts-mounting frame (8) is fixed to the side members (5) at the substantially same level as the side members (5).
Further, for the same reason, the center of gravity of the motor unit (15) is relatively high, thus, the movability is worsened.
To fix frame-side-brackets (29) to the side members (5), a worker stands under the frame-side-brackets (29) to handle bolts/nuts (32), and then the worker has to move above body-side-brackets (30) to handle other bolts/nuts (33). Accordingly, fixing the parts-mounting frame (8) to the side member (5) is awkward using the technique of the related document 1.
On the other hand, although it must be effective for absorbing vibration and noise from the motor unit (15) to equip bushes at mountings (21 and 22), it is difficult to prevent the motor unit (15) from rolling due to driving of the motor unit (15). Fundamentally, the related document 1 is totally silent about the importance of suppression of the motor unit (15) roll.
Namely, by the technique of related document 1, mountings (21 and 22) support the motor unit (15) against the force input from the motor unit (15) due to the roll, and accordingly, it is difficult to avoid increasing the size and durability of the mountings (21 and 21). Consequently, it is difficult to downsize and cost-cut by the technique of related document 1.
Further, during acceleration of the vehicle, roll is enhanced due to inertia of the motor unit (15).